Gut Microbes can Worsen Neurodegenerative Conditions

Research has shown that microbial organisms in the gut can influence health and disease in many ways. More recent research has shown that gut microbes may cause or worsen neurodegenerative conditions such as Parkinson’s disease and Alzheimer’s disease. Now researchers at the University of Louisville and University of Michigan have proposed a new term to describe an interaction between gut microbiota and the brain. The term “mapranosis” has been coined for the process by which amyloid proteins produced by microbes (bacteria, fungi and others) alter the structure of proteins (proteopathy) and enhance inflammation in the nervous system, thereby initiating or augmenting brain disease.

The researchers hope that by giving the process a name a greater sense of awareness of the process will occur and help with additional research needed for therapeutic opportunities. The researchers feel it is important to define the ways in which gut bacteria and other organisms interact to create disease. Research into microbes that inhabit humans has increased in recent years. Genomic analysis has begun to reveal the full diversity of bacteria, viruses, archaea, fungi, and parasites living in and on the body, with the majority of them in the gut. More recently, researchers have begun to explore how the proteins produced by microbes in the gut influence functions in other parts of the body. The relationship between the microbiota and the brain has been called the “gut-brain axis.”

The clumping of misfolded amyloid proteins, produced by neurons in the brain, are associated with neurodegeneration conditions such as Alzheimer’s disease and Parkinson’s disease. It is known that patterns of amyloid misfolding of neuronal proteins are involved in age-related brain diseases. Recent studies suggest that similar protein structures produced by gut bacteria, referred to as bacterial amyloid, may be involved in the initiation of neurodegenerative processes in the brain. Bacterial amyloids are produced by a wide range of microbes that inhabit the GI tract.

Prior work by one of the researchers who coined the term showed that when E. coli microbes in the gut of rats and worms produced misfolded amyloids, the amyloids produced in the brains and intestines also misfolded, known as cross-seeding. The researchers work shows that microbial partners make functional extracellular amyloid proteins, which interact with host proteins through cross-seeding of amyloid misfolding and trigger neuroinflammation in the brain. The researchers point out other ways that the gut and brain are connected. The gut-brain axis is bidirectional (goes in both ways). The microbiota may induce oxidative toxicity and inflammation that contributes to neurodegeneration. The microbiota modulates immune processes throughout the body. The microbiota produces metabolites that may be either beneficial or damaging.

This work suggests that you may want to keep an eye on what you eat to help improve the health of your gut to prevent neurodegenerative conditions from developing. In additional perhaps you may want to consider taking a probiotic to help improve the gut health.

Reference: Robert P. Friedland and Matthew R. Chapman,The role of microbial amyloid in neurodegeneration, PLOS Pathogens, 2017.

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